I don't think he was trolling me. I think he really believes it, and no amount of facts matter. Welcome to the world of alternative facts, where you can make up anything you want, and it must be true.
In fact, to give him the most amount of leeway I possibly can, he probably thinks things work the way he says they do because the way Worldcons are organized is insane. We build up a million-dollar one-shot convention, investing vast amounts of volunteer time and money, and then shut it all down. This is so illogical that he (and presumably others) are convinced that it's not really true, because they personally would never do so. Since they personally would never do it, they know that nobody else would do so, either.
This is yet another reason I encourage all future Worldcons to adopt a name that starts with "Worldcon." Not an individual nickname. Either Worldcon N or Worldcon YYYY: The Nth World Science Fiction Convention. Our traditions have played us false with the rest of the world, including fans who go to SF conventions.